This thermoplastic elastomer is present in a substantially solid state suitable for use as a binder for a propellant, explosive, and/or gas generant of a supplemental restraint system. The thermoplastic elastomer is formed from a composition including A blocks which are crystalline at temperatures below about 75° C. and B blocks which are amorphous at temperatures above about −20° C. The A blocks are derived from oxetane derivatives and the B blocks are derived from oxiranes and derivatives thereof. The A blocks and B blocks are end-capped with a diisocyanate having a first isocyanate moiety that is substantially more reactive with the terminal groups of the blocks than the second isocyanate moiety, whereby the more reactive first isocyanate moiety is capable of reacting with the terminal groups of the blocks, leaving the less reactive second isocyanate moiety free and unreacted. The end-capped A blocks and the end-capped B blocks are linked together with a linking compound having two isocyanate-reactive groups which are sufficiently unhindered to react with the free and unreacted isocyanate moieties of the end-capped polymers.
这种热塑性弹性体在实质上固态存在,适用于作为辅助约束系统的推进剂、爆炸物和/或气体发生剂的粘合剂。该热塑性弹性体由一种组合物形成,其中A块在约75°C以下的温度下具有结晶性,而B块在约−20°C以上的温度下是非晶态的。A块源自氧杂
环丙烷衍
生物,而B块源自环氧烷及其衍
生物。A块和B块的端基被二
异氰酸酯端基化,其第一个
异氰酸酯基团与块的端基相比,反应性更高,因此更具有反应性,能够与块的端基反应,留下较不反应的第二个
异氰酸酯基团自由而未反应。端基化的A块和端基化的B块通过一种链接化合物连接在一起,该链接化合物具有两个
异氰酸酯反应基团,这些反应基团足够不受阻碍地与端基化聚合物的自由未反应的
异氰酸酯基团反应。